坎昆升级来临 哪些L2做了适配？

作者：Maggie@Foresight Ventures

TL;DR：

• 坎昆升级将于2024 年 3 月 13 日推出，EIP4844即将上线。Danksharding是以太坊路线图的核心，这次升级是实现Danksharding的第一步。

• Ethereum  L2适配EIP4844后，交易手续费大幅下降，L2的TPS成倍提高。用户会感觉到交易速度更快、成本更低、体验更流畅、反应更灵敏。这些L2上会有更复杂更大型的Dapp应用。

• Optimistic rollups适配EIP4844更简单，ZK rollups适配更复杂。以太坊没有预编译合约支持BLS12-381椭圆曲线，导致部分ZKP验证难度大，阻碍了ZK rollups适配EIP4844的进度。

• 椭圆曲线的问题可以通过两种方式解决，1. 等待以太坊对BLS12-381椭圆曲线进行预编译；2.用另一种证明方式来达到同等目的，使用以太坊预编译支持的BN254.

• 目前，Arbitrum、Optimistic、Starknet、zkSync、Scroll、Polygon zkEVM以及新L2 Morph都在适配EIP4844。其中，Arbitrum、Optimistic 和Starknet表示坎昆升级后会实施对EIP4844的适配。Morph则率先发布了创新的zkSNARK zkEVM适配方案，这将是第一个适配EIP4844的zkSNARK zkEVM

一、背景

2020 年，以太坊发布的 “以 Rollup 为中心的以太坊路线图”，以及第二年Vitalik发表的「Endgame」中描述的以太坊的最终图景，确定了以太坊的大方向：优化以太坊的基础层建设，为Rollup服务。

以太坊设计了Danksharding的分片技术以提高以太坊作为数据可用性层的可用性。它将显著降低L2的交易手续费，提高Rollup的TPS，实现以太坊的大幅扩容

直至今年，以太坊坎昆-德内布（Dencun）升级终于在 2024 年 3 月 13 日推出，EIP4844即将上线，这次硬分叉可以说是以太坊实现Danksharding的第一步，是以太坊路线图核心中的核心。

关于什么是DA层，Danksharding的技术原理，EIP4844的内容，请参考去年我写的一篇技术文章：DA（数据可用性）Summer 将至？https://foresightnews.pro/article/detail/33575

二、坎昆升级如何利好L2？

EIP4844引入了一种新的交易类型，称为blob-carrying交易。每个blob-carrying交易都可以“携带”一个 Blob 列表 。Blob 是一个数据包，大约 125 KB。Blob存储的时间很短，仅4096个epoch，略多于18天。

1. L2交易手续费大幅下降。由于Blob不需要永久存储，Blob相比于区块空间更大更便宜。Blob 可以在相同的 gas 消耗下存储比 Calldata 多 10 倍的数据。适配了EIP4844的Rollup可以将交易数据存储在 Blob 中，将交易费用降低一个数量级。

2. L2的TPS成倍提高。目前每个区块目标是3个Blob，最多允许 6 个 Blob。区块只有 90KB，而每个Blob大约125KB。引入Blob相当于为区块额外扩展了几倍的空间可以用来存Rollup的数据，因此Rollup的TPS也能成倍增加。且Toni和Vitalic写的“On Increasing the Block Gas Limit”中表示，会通过增加区块Gas limit和非零Calldata bytes的价格，实现更小、变量更少的区块大小，从而未来可以增加更多Blob。Blob更多则存储空间会更大。

对最终用户而言，Ethereum  L2适配EIP4844后，交易速度更快、成本更低、体验更流畅、反应更灵敏。这些L2上会有更复杂更大型的Dapp应用。

三、L2如何适配EIP4844？

L2如何适配EIP4844呢？我们需要分Optimistic Rollup和ZK Rollup来分别讨论。

Optimistic Rollups适配EIP4844

Optimistic rollup是通过欺诈证明来保证rollup执行的正确性的。即节点首先选择相信状态的转换是正确的，除非有人在规定的时间段内发起欺诈证明，证明之前提交的是状态转换是不合法的，则该状态转换会被撤销。

Optimistic Rollup适配EIP4844相对ZK rollup来说更简单。把L2的交易都通过Blob-carrying交易提交到L1即可完成适配。此外，就是要调整欺诈证明使之适配EIP4844，这部分就可以慢慢做了。毕竟，很多optimistic rollup至今也没上线欺诈证明。上线了欺诈证明的，发现两年多都没有一个欺诈证明提交。

1. L2交易提交：Rollup提交的时候，使用Blob-carrying交易，将Rollup数据存储在Blob中。Blob-carrying交易的payload是rlp([tx_payload_body, blobs, commitments, proofs]) ，其中

• tx_payload_body - 是标准 EIP-2718 blob 交易的 TransactionPayloadBody。

• blobs - Blob 列表。一个交易最多包含两个blob。

• commitments - Blob的KZG承诺列表。

• proofs - Blob和对应KZG承诺的证明列表。这个证明是会被ETH节点所验证的。

• 调整欺诈证明：

• 首先，证明者和挑战者需要多轮交互等方式找到争议点。

• 然后将争议点提交到L1上做判定。适配EIP4844则有可能还需要证明这个争议点的数据存储在某个Blob上。

• 由于Blob数据大约18天后会被删除，因此挑战期必须在被删除之前，这一点现在的optimistic rollups都是满足的。一般挑战期不超过7天。

ZK Rollups适配EIP4844

ZK rollup是通过ZKP来证明L2状态转换是正确的。ZK rollup适配EIP4844相对optimistic rollup来说更复杂。






The author Cancun upgrade will be launched on, and will be launched soon. This upgrade is the core of the roadmap of Ethereum. This upgrade is the first step to realize. After adaptation, the transaction fee will be greatly reduced and doubled. Users will feel that the transaction speed will be faster, the cost will be lower, the experience will be smoother and the response will be more sensitive. These will have more complex and larger applications, and the adaptation will be simpler and more complicated. Ethereum does not support elliptic curves with precompiled contracts, which leads to some difficulties in verification and hinders the adaptation progress. There are two ways to solve the problem of elliptic curves. Ways to solve the problem of waiting for Ethereum to precompile elliptic curves to achieve the same goal with another proof method. The current and new capitals supported by Ethereum precompile are adapting to it, which means that Cancun will implement the adaptation. This will be the first adaptation background. The road map of Ethereum released by Ethereum in 2000 and the final picture of Ethereum described in 2000 determined the general direction of Ethereum and optimized the foundation of Ethereum. The basic layer construction is the fragmentation technology designed to serve Ethereum to improve the usability of Ethereum as a data availability layer, which will significantly reduce the transaction fee and realize the substantial expansion of Ethereum until the Deneb upgrade of Ethereum in Cancun this year is finally launched on March, this hard fork can be said to be the first step in the realization of Ethereum. For the content of the technical principle of Ethereum roadmap, please refer to a technical article I wrote last year on data availability. How to upgrade Cancun in the coming two days has introduced a new transaction type called transaction. Each transaction can carry a list, which is a data packet. The storage time is very short, only a little more than a day. The transaction fee is greatly reduced. Because it does not need permanent storage, it is bigger and cheaper than the block space, and it can store multiple times of data at the same consumption. Adapted transaction data can be stored in it, and the transaction cost will be reduced by an order of magnitude. At present, the goal of each block is the most. Allowing only blocks and introducing about several times more space for each block can be used to store data, so it can also be multiplied, and the sum of the written data means that smaller variables and fewer block sizes can be realized by increasing blocks and non-zero prices, so that more storage space can be added in the future, and for the end users, after adaptation, the transaction speed will be faster, the cost will be lower, the experience will be smoother and the response will be more sensitive, and these will have more complex and larger applications. How to adapt? Adaptation? We need to discuss separately that adaptation is to ensure the correctness of implementation through fraud proof, that is, the node first chooses to believe that the state transition is correct, unless someone initiates fraud proof within a specified period of time to prove that the state transition submitted before is illegal, the state transition will be revoked. Adaptation is relatively simple, and all transactions can be submitted through transactions to complete adaptation. In addition, it is necessary to adjust the fraud proof to make it adapt, and this part can be done slowly. After all, it is very simple. Many fraud certificates have not been online so far. The discovery of fraud certificates has been online for more than two years. No fraud certificate has been submitted. When the transaction is submitted, the data is stored in the database. The transaction is a list of standard transactions. A transaction contains at most two commitment lists and a list of certificates corresponding to commitments. This certificate will be verified by the node. The adjustment fraud certificate first needs multiple rounds of interaction between the prover and the challenger to find the disputed point, and then submit the disputed point to the website for judgment and adaptation. Then it may be necessary to prove that the data of this controversial point is stored in a certain place, because the data will be deleted in about days, so the challenge period must be before it is deleted. Now all of them are satisfied, and the general challenge period does not exceed days. Adaptation is to prove that the state transition is correct, and adaptation is relatively more complicated. 比特币今日价格行情网_okx交易所app_永续合约_比特币怎么买卖交易_虚拟币交易所平台

1.L2交易提交：这一步Optimistic Rollup是相似的。

2.ZK证明提交：与适配前的ZK Rollup相比，除了做状态转换的ZKP证明以外，还需要多证明一个过程。即证明blob commitment和transaction batch是对应的，从而保证状态转换证明的输入是正确的。

打个比方：状态转换的ZK电路能生成计算过程a + a = b的证明。当（a=1,b=2）和（a=2,b=4）时生成的ZKP都是合法的。因此我还需要提供一个证明，证明我当时提供的输入是（a=1,b=2）而不是（a=2,b=4）。

这一点在适配EIP4844之前是不需要做的，因为数据就直接存储在Calldata中可以直接读取，确保了输入不会被调包。用了EIP4844后，Blob数据无法直接读取，只能通过一个新的电路来证明这一点。

用STARK的ZK rollup(如Starknet)更容易实现这种证明机制。而这对于用SNARK的ZK rollup是存在挑战的，原因是：EIP4844的blob commitment使用的椭圆曲线是BLS12-381，而ETH的预编译合约只支持了BN254，由于曲线不同，导致我们难以直接在智能合约中验证blob commitment完成证明。

1. 用SNARK的zkEVM/zkVM需要解决第2点中提到的由于曲线不匹配无法生成ZK证明的问题。
   

• 等待Ethereum支持BLS12-381的预编译合约。这会很漫长。

• 采取另一种证明方式来证明。要设计新的电路，必须用预编译合约所支持的BN254椭圆曲线。目前，我们看到Morph采用了这个方法。这也使得Morph成为第一个完成EIP4844适配的zkEVM。

Morph 的 EIP-4844 zkEVM 集成解决方案请参见：https://medium.com/@morphlayer2/morphs-solution-to-eip-4844-zkevm-integration-7f469910478f

四、有哪些L2适配了EIP4844？

Optimistic rollup中，Optimism和Arbitrum已表示致力于采用 EIP-4844，并与其社区密切合作来测试和部署必要的更新。Arbitrum属于Stage 1的Rollup， 安全性相对较好。涉及到需要将欺诈证明适配EIP4844的问题。Optimistic rollup属于是Stage 0的Rollup，目前还没有欺诈证明，适配起来更容易，但安全性不够高。

ZK rollup中，使用STRAK和SNARK的rollup适配难度是不同的。用STARK的rollup适配EIP4844更简单，Starknet是其中的代表。Starknet发表了文章表示坎昆升级后会实施对EIP4844的适配(文章链接)。用SNARK的rollup，zkSync也在探索如何利用携带 blob 的交易来进一步降低成本并提高性能。Scroll则是在去年发表了一篇文章介绍了适配EIP4844的思路（文章链接）

最令人映像深刻的是Morph, 他是一个Optimistic ZK Rollup，率先发布了zkEVM适配EIP4844的方案，可以说是第一个完成EIP4844的zkEVM  Rollup。

Optimistic ZK Rollup结合了两类Rollup的优势。它乐观地相信Sequencer提交的执行结果，允许对结果产生怀疑的人发起挑战。只有在发起挑战时，证明者才会生成ZKP来证明执行结果的正确性。它拥有Optimistic rollup的效率，又拥有ZK rollup的ZK证明的可靠性。